The concentrations of reducing sugar descend to about 120 mg/
L at 8 h except T70 of 195 mg/L. Afterwards, the concentrations of
reducing sugar first increased to 270 mg/L for T00–T30 and 300–
460 mg/L for others due to the conversion from some digestible
portions by rumen microorganisms, then following by similar decreases
to about 110 mg/L till 48 h. After 48 h, the concentration
of reducing sugar for all the fermentation experiments was kept
pseudo-stable with slight fluctuation, indicating that the hydrolysis of refractory components became the restrict step for the fermentation
of maize straw by rumen microorganisms.